In a 72‑year‑old man with iron‑deficiency anemia, decreasing ferritin, three positive fecal immunochemical tests, a normal colonoscopy performed 13 months ago (with removal of a 5 mm benign adenoma) and a normal upper endoscopy performed 16 months ago, what is the appropriate next diagnostic work‑up for occult gastrointestinal bleeding now that capsule endoscopy is unavailable?

Appropriate Next Steps for Persistent Occult GI Bleeding with Unavailable Capsule Endoscopy

Given this patient's persistent iron deficiency anemia with positive FIT tests and negative bidirectional endoscopy over a year ago, repeat upper endoscopy and colonoscopy should be performed immediately, followed by CT enterography if these remain negative. 1, 2

Why Repeat Endoscopy is Critical

The most important action is to repeat both upper endoscopy and colonoscopy before pursuing small bowel evaluation, even though the initial studies were performed relatively recently. 2, 3 Here's why:

• Lesions are commonly missed on initial endoscopy: Upper GI lesions frequently overlooked include Cameron's erosions in large hiatal hernias, fundic varices, angiectasias, Dieulafoy's lesions, and gastric antral vascular ectasia. 4, 3
• Colonoscopy misses lesions in 14-28% of cases: Angiectasias and neoplasms are particularly easy to overlook. 4, 3
• Repeat endoscopy has proven worthwhile: In patients with obscure GI bleeding and persistent anemia or overt bleeding, repeat endoscopic examinations frequently identify previously missed lesions. 2
• The 13-16 month interval is significant: New lesions may have developed, or previously subtle findings may have progressed. 1, 2

Algorithmic Approach When Capsule Endoscopy is Unavailable

Step 1: Repeat Bidirectional Endoscopy

• Perform both upper endoscopy and colonoscopy at the same session for efficiency. 4
• During upper endoscopy, obtain small bowel biopsies to evaluate for celiac disease (present in 2-3% of iron deficiency anemia cases). 1, 3
• Use meticulous technique including examination of blind areas and consideration of cap-fitted endoscopy to detect subtle angiectasias. 2

Step 2: If Repeat Endoscopy is Negative, Proceed to CT Enterography

CT enterography is the appropriate alternative when capsule endoscopy is unavailable. 2 This modality:

• Has excellent sensitivity for mass lesions >10mm (>90%). 4
• Can identify small bowel tumors, which are the most common cause of obscure bleeding in patients under 50 years. 2
• Detects extraintestinal pathology such as renal tumors and lymphomas. 4
• Is particularly appropriate for patients with relative contraindications to capsule endoscopy such as prior surgery or potential stenosis. 2

Step 3: Consider Push Enteroscopy or Double-Balloon Enteroscopy

If CT enterography identifies a proximal small bowel lesion or if bleeding persists:

• Push enteroscopy can evaluate the proximal small bowel beyond the ligament of Treitz. 4, 5
• Double-balloon enteroscopy allows both diagnostic evaluation and therapeutic intervention for small bowel lesions. 2, 5
• These techniques are complementary and can provide tissue diagnosis and treatment. 5

Critical Considerations for This 72-Year-Old Patient

Age-Related Bleeding Patterns

At 72 years old, this patient is in the demographic where vascular lesions (angiectasias) account for up to 40% of obscure bleeding cases. 4, 3 These lesions:

• Are frequently subtle and easily missed on initial endoscopy. 4
• May be intermittent in their bleeding pattern. 6
• Require careful endoscopic technique to identify. 2

The Significance of Persistent Positive FIT Tests

Three positive FIT tests indicate ongoing blood loss that demands source identification, regardless of the negative prior workup. 1, 2 The fact that the bleeding source remains unidentified after initial evaluation does not diminish the need for continued investigation. 1

Declining Ferritin is a Red Flag

Progressive iron deficiency with declining ferritin indicates continued blood loss that is clinically significant. 1 This is not a situation for observation—active investigation is mandatory. 4, 1

Common Pitfalls to Avoid

• Never assume the small adenoma removed 13 months ago explains current bleeding: A 5mm benign adenoma would not cause persistent positive FIT tests and progressive iron deficiency. 1
• Do not accept "test unavailable" as an endpoint: Multiple alternative diagnostic pathways exist. 2, 5
• Avoid attributing findings to age or medications without complete evaluation: Even in elderly patients on aspirin or anticoagulation, full investigation is required. 4, 1
• Do not skip repeat endoscopy to jump directly to small bowel imaging: The yield of repeat endoscopy is substantial and must be performed first. 2, 3

Additional Diagnostic Considerations

Helicobacter pylori Testing

If repeat endoscopy is negative, test for H. pylori and eradicate if present, as colonization may impair iron uptake and increase iron loss. 4

Renal Tract Evaluation

Perform urinalysis to exclude renal tract bleeding, as approximately 1% of patients with iron deficiency anemia have renal tract malignancy. 4 If hematuria is present, proceed with renal ultrasound. 4

Angiography for Active Bleeding

If the patient develops hemodynamic instability or requires transfusion, visceral angiography with embolization becomes appropriate for both diagnosis and treatment. 4, 2

What Should Have Been Offered Initially

The gastroenterologist's statement that "capsule endoscopy is not available" without offering alternatives represents suboptimal care. Standard alternatives include CT enterography, push enteroscopy, or double-balloon enteroscopy—all of which are widely available diagnostic modalities. 2, 5 The patient should request either these alternatives or referral to a center where comprehensive small bowel evaluation is available. 5, 7